Metal oxide TFTs are components widely used in basic circuits of various electronic systems. The metal oxide TFTs have many advantages, such as high carrier mobility, low processing temperatures, high stability, high transparency, etc. FIG. 1 depicts a typical bottom-gate TFT device 1. In a conventional process of manufacturing the bottom-gate TFT device 1, in order to form a source electrode 102 and a drain electrode 103 of the bottom-gate TFT device 1, a conductive layer and a photoresist layer (not shown) are sequentially formed on a gate electrode 101 via a gate insulation layer 104 and a semiconductor layer 105. The photoresist layer is exposed via a photomask (not shown) disposed above the photoresist layer and then is developed to form a patterned photoresist layer. Further, a part of the conductive layer is etched according to the patterned photoresist layer. Accordingly, the rest of the conductive layer remained on the semi-conductive layer 105 are respectively used to form the source electrode 102 and the drain electrode 103.
However, due to the limited exposure accuracy in photolighography and a misalignment between the photomask and the bottom-gate TFT device 1 may occur, overlaps are generally formed between the gate electrode 101 and the source, drain electrodes 102, 103 resulting in generating a gate-source parasitic capacitance (Cgs) and a gate-drain parasitic capacitance (Cgd). The gate-source parasitic capacitance and the gate-drain parasitic capacitance have a poor influence (impact) to a work performance of a pixel circuit (not shown) including the bottom-gate TFT device 1. Accordingly, an electronic device employed the bottom-gate TFT device 1 may have a poor image quality, including image flicker and sticking.
What is needed, therefore, is a metal oxide TFT device, a method of manufacturing the metal oxide TFT device, a pixel circuit, and a method of manufacturing the pixel circuit which can overcome the described limitations.